SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'da57476532a28d54d5fb6fb4ca9d7ab0109b9445fe1ed0a991cdea26757e10ae' 
  AND token = 'r8L6ZmnLnPC6peZjIXrHO/JCqi0zoxioJd3maf/Z3bA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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