SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75874d668b2994f2122b4362d42a54dc4c35b6ceb47e1baf9fde9a0d6bc8201a' 
  AND token = 'AkHHxvTGW/EyKyozN0DNtsPcyvZMkK9YMk2QVcLDJh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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