SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8baa5243297acc9569126febc1cdd2d08a295cde2e1f196c8d0d40ea3f288156' 
  AND token = '8u7TZw/fQKEPKH2A8yH/7yVBfU2tN1vxbMO2h6VzcJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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