SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4313700d9d45dbe0edc79294b7d72accc9756af1982686f66fdf94c963cdfcd' 
  AND token = 'aTEwRxr5HP6qkMMISHgb8Y96aSJvdjcTHEKAeCqdJuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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