SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dedc70a8fe9c2c5225324e18c8aacaeccc40603904b7b5c1d4a400f6c82a4986' 
  AND token = 'vmkJDXixGJxHaSqfkqrQELaQErhXQozPxRqsCtDHAws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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