SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0899cb61472a4208b646c756c63d77e8b0a5e06214de31925b512961ca7c0ed9' 
  AND token = 'FE3w7XZedAqtWiJ4ZMmkG+8z6OUG/8w46njr7V0CJAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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