SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c97501e9a32bc65f1834c37b32ddcb97eea3926548880d7c3e14b94de5984ec' 
  AND token = '7Kl4R3t2kpu19pgPhM4VqsPUD6GLvfU2kcALnaa2Yn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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