SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57226850d4dcc6a2d789e14e0a77f3e55588b41cf2b45b1f8daa54b943e5ecc4' 
  AND token = 'S6ckRHbgoziBmTPKRDPS3bBxy+l/aENiORLAOhqM9wI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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