SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fafcb789ddb83ce1ffc5de6bca3ce1232efdf3597614f82b071ce4d63967e94e' 
  AND token = 'hx7dCGnS2WiqnjtWs6HDykIgpFT3qulcLtwesAaetok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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