SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f59478565c314192bbd8cdcd21c6b54655f84a530c3cbed7f6b7bc11233cc49b' 
  AND token = 'nBDoVSra1nhSQkmPVNZ16CZjr++hHBc9q9MhRC+EgAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}