SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '835e622cf15b0b660d6c6522b313dbf81b8c2496bf965d9c531e3b1200917878' 
  AND token = 'aSNgs+go4YzowsQ/uyx5eJb6JSaVPmb9Ka4q0X5vrfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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