SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'faca2b9caced22abf3e33f3afd69033755ac0ff527d00359d89dcec221839dd1' 
  AND token = '3RXpKm9/Ff9/cnjF8UE0pWVrAeG4scWokVlnxipqh3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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