SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '684e0e85b5f5a247cf05359cd12395256f677642d23b34581396f75af8dd9389' 
  AND token = 'Enr1wgud+03OrQZwTp/mUyzZEluj7q3C36H+915JUgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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