SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f859b37c1feea0ec2f697c3e7bd8593cfcdde5d477b3b3ddf24284ee4b689811' 
  AND token = 'bnoDbmswCKW6iVuoBUV7p4y62vDRFkS5Eh1dOyWhd5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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