SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e6e364385cb3fe60f7e58d462831095c81c14c01f0e8f9bf6148164b4589942' 
  AND token = '6sPyTAoQMyoZK6poNqcyjuK8cd1aaLLUOZngRxkMiOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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