SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '704481fdf51e68615f2fed73e53711f30d0aa912d13fb58319afb705cbb822b7' 
  AND token = 'GybpnlgbZbFRbSFhoI7lp1els4ooAa1Yjfxn6+/IXpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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