SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3a480af5112960fecb1f5259b9b102206254a91a7e046872f8823f936eff394' 
  AND token = '++WTS6BxnKdc3py82gCHUY7oIjXV6ZjLza8w/theExE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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