SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af8bcb0a5722b6d8fa0a159913d2ee54139a9534980650b0930d6dffc0cb1475' 
  AND token = 'uPAA52Eejngst03B4qAhA6hStC7Le0GLotaN9IiDr74=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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