SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af973d09f2a14f292d6078638c8bb313e9437792eb7ff6404e202fc37101c63c' 
  AND token = 'FCUzmXaQRONri3EhAq77oTOONglUQdZc4DYkds5VTKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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