SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac7a429d16816234e1557499976a9d5c4b3169d8f54f6d5d69dc774eb8ff2d9c' 
  AND token = 'MJp0xYK9Gq53aLH5/9ZKrvu7P31Vxk3v28Hhb5jLoQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}