SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd15a6c162785a266bff129c84dc262465110f62c72d81809b07278ee60cf0f6' 
  AND token = 'ERWjzkZkGEJ8ZgTXrg87Tx/seYi1FcD+7aDUi1NFxqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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