SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28df729939819919587a42402d79c3a0efaaa8e384464eb29b2608cb468167e3' 
  AND token = 'O6k6VLIhOErG+QpZgUl2snKYworsMvOPvbZ8smHnZ+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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