SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f2ea688c1a5461dc4f08df4e46912ca83cc6fb061b9133e81d7db7826f60615' 
  AND token = 'CvK59iMCjunIZr5yfDrkAtXXxZarSJM5VaQKhMy4Hl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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