SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '482d7f48905c6be1c4109100a5edebbbf6b5edd656b0d87e286b2c3ad48d5fa1' 
  AND token = '/0+CjFGEMotu4vfBXxg5KVOVwDurGVx9FSgXsh1HQnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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