SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19d3872a4c7d40d0b00455176a4acd37875b9ee6e808aae943472c6f25e5ab3c' 
  AND token = 'pRs7sBNa89FZfpn20Xey5rPtVpFA/GP0MpwAX+Gl9lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}