SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95bfdc1c04567812ba75e7129f1110ebd9daefd2046febeda0346de2ce49cb4a' 
  AND token = 'GXKZdEku57Qd4eN3bsTP66wrt+wxrlizgh5rD8lpSrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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