SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4755c8a9c92282c19be24db82fa3a326f6c2289eb87e59b405a925416ab326e' 
  AND token = 'F13tOm7IGcIFnEwEaEgTaLuijDhEln7neJUuIYhtOb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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