SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e6a0b06daf022aaf61d12acc527e2ec32d7a7bc0e82ce740adbe833197581a6' 
  AND token = 'uQPBwV99C9MkjzCTaBb8V9Bh+RiTD01//r1XSd7qiDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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