SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7746d3cd41c9a32c9387732ed90ddcd1432289dbe1c36b679b3e3c54560e17' 
  AND token = 'Qe5cCb4ztMgZ2ILjOWmKOQ8dEyUW27eZLNFPkCQmlP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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