SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4048767c9999163006877ac51824bf475441dfefcc62f90a575ef298ac9ccaaf' 
  AND token = 'oeCeRU7MwUXaUDw+Cy1e277WRzOOD4RKOSBQU6BCusw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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