SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb999d31beeb1044b83c6588203494c28d61da484ef97655e2191ee99a3c965e' 
  AND token = 'siy1Dyp8MfyunPFJh8hqxSp0NUWEflcr1UenPTAtbzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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