SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdab3dc87415f5d10ea9e6ab232fff99430af05709d6cf935297787010294da4' 
  AND token = 'iSNdUaFj3AONyTRM3d5eNtSeQmOvOFIFaaxbkIJMTH0=' 
  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"
    }
  }
}