SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dabb65eab501d8ce2b64dc8e6f527aa94f225d72cc2222e21291807f1419d03' 
  AND token = 'R4IVruaQzAdMgphI6uHgRLUcFRpLtPropZQxkbdbo64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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