SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68df3314b17ece18669d251a7bba6ece44e9bf6c4109ac6f1c80664d30255e69' 
  AND token = 'h2R7tpfI6NyGt+zmIjnb1k2Hu4d6d8mdOYj26XMiYmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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