SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e31163e930e9ab348fdaa86cecd4e75993549b4cf9bd9e3b8cbcca6ca1fb63a' 
  AND token = 'IO/HZ0gCmdelDD5cQ/yCRS8ueLpqzxgsnkq97Y1pt7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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