SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17becd986c76daeda3dbc938a1253fb04776a77f62b6e6789a584c14a79358f7' 
  AND token = 'I2ji9mxYybLavrAY+SLEGKLhKMy47T5yAguOHNjMWxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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