SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ee92c1b3c4232622f925aa7cc94da0449f5241dd9521bca14e2a68e54115c02' 
  AND token = 'INGTvJ5yfD4zGLZUgDqvplI23fw3dfYAWK1P2/en+VU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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