SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '168d52eff2eb046c3afce07091685bfcfbbf9593611289ca6c9c192b1a57c523' 
  AND token = 'hKgYbWeJs36zCcA9E6otvzKRs3JCyCJu8NM/lpzGgNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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