SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65ce6cc91003b5088c637d256b46410019542562bd84626406524a88cb19d0aa' 
  AND token = 'CwTjrZo7yv9EIMeEKFbo1gks8GvKKxM5AgomjLw72WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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