SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3c0f2cd2ef5659387799cf541b25aaf3a46ab057af0c2e01938ebefeb4e05a1' 
  AND token = 'mI/5r+MR/fd7RPDSAvF+qSBSJ9jdkVwrsYXBxqgubVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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