SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6b66698d851f2f9e59eef2cc30be6f3c69e7908597fa871dd30760d165ad7f8' 
  AND token = 'w9sYWVLou3DPOknfXUGtldlLIWIe0p3lfmPwoPSJC+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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