SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b281858eb8816711d0b3a899d57cdbc0dd3b94113ef9c073602644c2b00d3916' 
  AND token = 'XB+SCdfVcDYxL87U3g+E/OQGz00NGBZbd0D7mGiYN3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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