SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcfa7329d601aefb988eae873118d103ac5da89a339f96c0e6c9288257dcbcd5' 
  AND token = 'sb4PLy+fiVCN3A2SUYLFyAzJusMFFqZJ2k9I1vfQ9oQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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