SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b90583a46dd8cb889dff3edfd7a833105d32f8bada35a2cc6148a02aa0020256' 
  AND token = 'X3J4wM9owJN99uPuVSmwAcJyruwhAQrrCbzt+Lzi96I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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