SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0bc39657725b8722ae1a947b1b77d641cf13e192ca94bf062fd09958ca1291c' 
  AND token = 'TH7R+AzTq1xqDXyqVdE4QjlhBzetJA4wWUmePzex3ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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