SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e922bcfa68a7966e213191059072b95e5d4b03236f4a9c90d4050d68e921daf' 
  AND token = 'ZITV/5+GbfNhjQsurB5I+Yi/56gpOIJu7EVGMnPR/qA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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