SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e60a6c9bea1ceb721655e7838f8e6a3274e34904a9c417bdf3981ffefc8e13f1' 
  AND token = 'am3k5IJOY6QBHvwCh5yIrhJR7bLpDt6dELuzVh1E7Ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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