SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46b74e275f420377d6e8dd102bec2eb43102958ca198112767ac9ac413ef27c8' 
  AND token = '6lb4PoLmuehfOSz4Lk2kTidzPwDPrfPAhH7loB3IBnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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