SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15fdcb4525c0ff6d78e61f699904be9367c152b7dfe46e8906602316d23bddd' 
  AND token = 'LLsKIRBdjcj9XGgTf9YzPSVKOPOjnPbfv+2q5GHUNZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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