SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f58a9cbaf5bb29d000ed28c685cea12c8d85d8466c795fc947dbf6bb66dc171a' 
  AND token = '8vE9JSsFAbCcv0QhZurR3vXOQpebndsE+GmXTTD4s14=' 
  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"
    }
  }
}