SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1b6bcb84be3e30592b5cb06ae92fe78851c72e68dac6ac052f6c79901aea55b' 
  AND token = 'PO5jcP2r9pcXnLtoQeKHMo8vkkniCM5Eem+XtPuxL4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}