SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7d837d0403d2c53314411c277084e480b7f829be62238bcdebb46d816f33fb3' 
  AND token = 'ahq7mthpDETj+hqXyc/GgH+nQ7OJjYSfKBh4H4n9YV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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