SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2256cab92e1041768923ba491e0688e77acc5ad125019fe4204ff18e6c7d27e6' 
  AND token = 'T+PiQ77mxUutmpFjwzJ7FFspFAb+GldwmHA/jKFz1xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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