SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bb55ee6b62181a13bd2c51963746dfed5211a41ecf7f09e864a31969593c434' 
  AND token = 'F3SwHErOJbyfGVQ30+TjNgFEZ/oYpAqhovfhWxlzo08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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