SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f51979e4a4ab097f738fb345fae1f3314b676761da57d79223af7e9b2b56ab8f' 
  AND token = 'rXW93Vx2XLZxdwfFYBSzumBEGOexzw+zHo2exXL83NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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