SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf04083a0d2571c979e81882b27b68ab6a6352579c540f2f0622d855fc4d94b1' 
  AND token = 'QtWOB0yYvdVgawHMbtE0NTV3KRlpGxwV5Zqq3Y8+Xto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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