SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6248d076802fd252a39c2d71e2b6a530d9289ab7262c5e893d393d687ecb31fa' 
  AND token = '25AT5W1Kp0/gj14VV/7GbQO2V56+UhZ6FU+AUbTrd2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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