SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb80f1200ab1d5a1128076121f1ff25ecb520e886b620f7d74ea51fdf3984d87' 
  AND token = 'kvvi4AvzptUHfboGGFsyPDJMh+1xy6+uyacwFvHvFq4=' 
  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"
    }
  }
}