SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4a714999a6b45dd9f48fc22466184620289cec3fd90d7548f56ec37709388f9' 
  AND token = 'HARpN/JRVsY+ZT/V9s1VYPGYHvEhFlh2Yc38J9SWES8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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