SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cc78f81280925147626d33949d61a708d0957aa4dd3930a7fed9af02aa6e435' 
  AND token = 'q5uMuqw//BWHK+zZH/Tif0G29QqOQCOmV28gD/iAhhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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