SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c23744e7662bae07ecfaaab2a3cfa46609c44a70612febe570a386f66b97b519' 
  AND token = 'LDvzm/O6x/ddpVEr1Ch3uQEVGOXDrfXYdngi2Zl/qaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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