SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a968fd1aedc4d51642891d0daff9d5319d3ff4067b8ad2be232bc6b16fbf8f1' 
  AND token = '7q0KjDrMgbxoLC/EQnXBVjPJevMjFWC5hSa34SAQ9JY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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