SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50aeee94321e17f4656fe83a16379894ec26bdaf0892e62b444f8c6831b537d1' 
  AND token = 'mY/evKNvFACdqr1YQZrXBtP8YGjJ+fDzKRnc8ZHjWx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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