SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97378ebb851b3d2bb8d780c9407a0bb7f356191b1b342708c21b3b90a2feac3d' 
  AND token = 'iebcF0c71HGyzBK1oKP5CrOcIhmflpVO2ker44/pU/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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