SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af9696f602740c8062f36c4d1f9108b59ddde7c7ea825728f2769194d01bde7c' 
  AND token = '7UZ+HQjzPHhXX07ouUqMSFDKr01yB0JLJJPx+uuGh3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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