SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c363f26358044a62a9fc788e30407ceb5252c3a5dd40b000e94b0e621a708404' 
  AND token = 'RMbIvZvV7UmMQZ+mQv2nVzV9yNYXROQ4Hqfdtb3y+ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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