SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53bd7a6ea12421678df07834cdacbcf4331581dc44440067d46d045e7e91be57' 
  AND token = 'ZH61VCy32D/RAqyFI4rE62nVzzl7L1jdK5SDgn6MuC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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