SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fc43873697642af7c11e9b3ab54e65e638a42be52ca1dd92731dc8ad00fa215' 
  AND token = '0QyTjZlCdA5PeuOizv3Ya+3KLV5ZCmrP3xXc2sQ6oIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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