SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '787b6f97297b242a614d7d20fea9e0d02a16745ae9049f117922f296090020b8' 
  AND token = '2uzAVxY82jdTO1JEpO6hTRrb3ERvyOvCi76YyDgT3o8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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